[R] categorical column to numeric column

[Philipp Pagel]

> Let 'dd' be a data frame given as:
> 
> dd=data.frame(aa=c("a","a","b","a","b","b"),bb=c(1,1,1,2,3,4))
> 
> Now I want to create a column 'g' such that if dd$aa=a then dd$g=1 else
> dd$g= -1 .

You need to use ifelse instead of the if ... else construction:

dd$g = ifelse(dd$a=='a', 1, -1)

cu
	Philipp

-- 
Dr. Philipp Pagel                            Tel.  +49-8161-71 2131
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 and

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